Further insight into the temperature quenching of photoluminescence from InAs∕GaAs self-assembled quantum dots

Abstract

The possibility of controlling the photoluminescence (PL) intensity and its temperature dependence by means of in-growth and postgrowth technological procedures has been demonstrated for InAs∕GaAs self-assembled quantum dots (QDs) embedded in an InGaAs quantum well (QW). The improvement of the QD emission at room temperature (RT), achieved due to a treatment with tetrachloromethane used during the growth, is explained by the reduction of the point defect concentration in the capping layer. It is shown that the PL quenching at RT appears again if the samples are irradiated with protons, above a certain dose. These findings are accounted for by the variations in the quasi-Fermi level position of the minority carriers, which are related to the concentration of trapping centers in the GaAs matrix and have been calculated using a photocarrier statistical model including both radiative and nonradiative recombination channels. By taking into consideration the temperature dependent distribution of the majority and minority carriers between the QDs, embedding QW and GaAs barriers, our calculated results for the PL intensity reproduce very well the experimentally observed trends.

Electroluminescence And Spin-Polarized Hole Injection In InAs∕GaAs Quantum Dot Heterostructures

“…The capping layer thickness plays also an important role on the EL characteristics. These experimental findings are well reproduced by our modeling that includes the following steps: (i) Calculation of the electron and hole tunneling currents in the SD structure with oxide layer; (ii) Determination of the minority carrier's generation rate in the SAQDs and QW by a simplified analysis of the diffusion-drift transport in the near-surface region; (iii) Calculation of minority carrier's statistics out of equilibrium and determination of the light emission rates [7]. The modeling results (to be published elsewhere) convinced us that the EL of our direct-biased SDs indeed is due to the tunneling-mediated injection of holes from the metal into the light-emitting zone (SAQDs and QW).…”

Diagnostics of the efficiency of surface plasmon-polariton excitation by quantum dots via polarization measurements of the output radiation

“…Owing to a strong confine ment potential, the intense luminescence of QDs may be retained up to room temperature [17]. In [18], the main features of the photoluminescence of spherical QDs located in the vicinity of a planar metallic contact were investigated.…”

Наногетероструктуры С Улучшенными Параметрами Для Быстродействующих И Высокоэффективных Плазмон-Поляритонных Светодиодов Шоттки

“…В рассматриваемом нами диапазоне частот ω модуль действительной части ε 1 значительно превы-шает модуль ее мнимой части, которой мы поэтому будем пренебрегать. 1 Для вычисления ε 1 мы исполь-зуем модель Друде [6]. Согласно хорошо известным формулам [2], в случае достаточно толстого слоя ме-талла 1 закон дисперсии поверхностного плазмон-поля-ритона дается формулой k = (ω/c) ε 1 ε 2 /(ε 1 + ε 2 ), где k -величина параллельной поверхности раз-дела металл−полупроводник компоненты его волно-вого вектора, c -скорость света в вакууме.…”

“…Интересным объектом для исследования в качестве их активной области явля-ются квантовые точки (КТ) благодаря высокому огра-ничивающему потенциалу и, как следствие, способности сохранять высокую интенсивность люминесценции при комнатной температуре [1].…”